diff --git a/.github/workflows/cross.yml b/.github/workflows/cross.yml
index 62ae1c6eb89..21bc49da6c8 100644
--- a/.github/workflows/cross.yml
+++ b/.github/workflows/cross.yml
@@ -40,6 +40,7 @@ jobs:
           - powerpc-unknown-linux-gnu
           - x86_64-unknown-linux-musl
           - aarch64-unknown-linux-musl
+          - s390x-unknown-linux-gnu
     steps:
       - uses: actions/checkout@v3
         with:
diff --git a/aws-lc-fips-sys/builder/cmake_builder.rs b/aws-lc-fips-sys/builder/cmake_builder.rs
index 8d155008ff4..12a2d0e993e 100644
--- a/aws-lc-fips-sys/builder/cmake_builder.rs
+++ b/aws-lc-fips-sys/builder/cmake_builder.rs
@@ -79,13 +79,6 @@ impl CmakeBuilder {
     fn prepare_cmake_build(&self) -> cmake::Config {
         let mut cmake_cfg = self.get_cmake_config();
 
-        if ["powerpc64", "powerpc"]
-            .iter()
-            .any(|arch| target_arch().eq_ignore_ascii_case(arch))
-        {
-            cmake_cfg.define("ENABLE_EXPERIMENTAL_BIG_ENDIAN_SUPPORT", "1");
-        }
-
         if OutputLibType::default() == OutputLibType::Dynamic {
             cmake_cfg.define("BUILD_SHARED_LIBS", "1");
         } else {
diff --git a/aws-lc-sys/builder/cmake_builder.rs b/aws-lc-sys/builder/cmake_builder.rs
index 665e78283d9..c95cb2d64e1 100644
--- a/aws-lc-sys/builder/cmake_builder.rs
+++ b/aws-lc-sys/builder/cmake_builder.rs
@@ -61,13 +61,6 @@ impl CmakeBuilder {
     fn prepare_cmake_build(&self) -> cmake::Config {
         let mut cmake_cfg = self.get_cmake_config();
 
-        if ["powerpc64", "powerpc"]
-            .iter()
-            .any(|arch| target_arch().eq_ignore_ascii_case(arch))
-        {
-            cmake_cfg.define("ENABLE_EXPERIMENTAL_BIG_ENDIAN_SUPPORT", "1");
-        }
-
         if OutputLibType::default() == OutputLibType::Dynamic {
             cmake_cfg.define("BUILD_SHARED_LIBS", "1");
         } else {